1. Field of the Invention
The invention is generally directed to graphical user interfaces (GUI's) on computer systems. The invention is more specifically directed to a subclassing method that enables users to convert an on-screen listed item of a popup menu into a drag-and-drop object.
2. Description of the Related Art
Graphical user interfaces (GUI's) have found wide spread acceptance among computer users. Instead of having to remember a list of arcane command names, users can now intuitively click on (e.g., with the aid of a mouse button), or otherwise activate, graphical areas on the screen and thereby open previously-hidden lists of next-action choices. A further click or other activation on a selected one of the choice-items initiates a pre-programmed function associated with the chosen item.
Such menu-driven choice-making usually takes the form of the well-known popup menu, or scrolldown menu, or context menu. Any one or more of these choice-supplying mechanisms or their like is referred to herein as a `choice-listing menu`.
To invoke a choice-listing menu (e.g., a scrolldown menu), the user typically moves an on-screen cursor or another pointing indicia over part of a menu-dropping bar or over another such menu producing area. The user then clicks on a mouse button to initiate the unscrolling or other presentation and/or activation of the choice-listing menu (e.g., a scroll-down menu). Of course, means other than mouse clicking may be used for initiating the presentation and/or activation of a choice-listing menu. For example the user may instead press a predefined combination of `hot` keys on the keyboard to cause a desired menu to emerge onto the screen.
As its name implies, the choice-listing menu displays a set of choice-items to the user. The user is expected to select one of these choice-items. The represented function, if selected and activated, is thereafter executed.
One or more of the displayed choice-items in a first choice-listing menu can be a source area that unfurls yet another choice-listing menu from the first menu. The unfurled second menu can itself have further submenus.
Most users of the Microsoft Windows 3.1.TM. or Microsoft Windows95.TM. operating systems are familiar with the common menu-dropping bar that appears at the top of an active window that is opened under the Win16 or Win32 system kernel. The window's top bar (menu bar) typically contains areas marked as, FILE, EDIT, VIEW, HELP and so forth. If the user clicks on the FILE area, a scrolldown menu comes down from that area to present FILE-related choice-items such as OPEN, SAVE, SAVE AS, RENAME, CLOSE, EXIT. Selecting the OPEN choice-item implies that an OPEN FILE function will be performed and a to-be-designated file will be opened. Selecting the SAVE choice-item implies that a SAVE FILE function will be performed and a designated file (usually the currently open file) will be saved. Selecting the SAVE AS choice-item implies that a SAVE FILE AS.sub.-- new.sub.-- name function will be performed and a designated file (usually the currently open file) will be saved under a new name. The remaining FILE-related choice-items provided further file-related functions in accordance with their respective names.
If the user clicks on the EDIT area, a different scrolldown menu comes down from that area to present EDIT-related choice-items such as UNDO, COPY, CUT, PASTE, and so forth. The COPY function for example copies selected data to a clipboard area that is shared by application programs.
Once one of the presented choice-items is selected and invoked from an activated choice-listing menu, a corresponding, pre-programmed function is executed (such as OPEN FILE, SAVE FILE, COPY, etc.). A menu-invoked function can include the unfurling of a further menu that has further choice-items.
For each of the presented choice-items in a given menu, the user is given only the following choices: either select one of the choice-items in the displayed menu or do not select any item and instead close (rescroll) the choice-listing menu.
It may be advantageous to enable users to perform additional functions with the choice-items of choice-listing menus other than to either select one of the presented choice-items or not select any choice-item.